Stone countertops are widely used, such as home kitchen countertops, hand-washing countertops, and so on. The vanities in luxury hotel guest rooms use precious stone materials.
From the stone principle to the finished product, a countertop has to go through the following processes: material selection → large cutting → polishing → trimming → edge processing → potting, and drilling → polishing repair → trial assembly inspection → packaging → completion.
1. Material selection. According to the customer’s sample or production order requirements, select the appropriate rough stone. It is best to knock a block sample for polishing comparison, and observe whether the pattern, color, and particles are consistent. If it is a countertop with a regular thickness, you can also purchase a large board directly from the large board market. The point of attention when selecting materials is to choose blocks or slabs with the same color, the same pattern, the same particle, and close to the density. At the same time, there are no defects such as cracks, stone gall, color lines, flower brushes, etc. At the same time, large plates should pay attention to thickness and size issues.
2. Big cutting. It is the process of cutting the blocks into rough boards with a circular saw or sand saw according to the customer’s processing requirements. After cutting, an inspection should be carried out first, the qualified rough boards are kept for use, the unqualified ones are picked out, and the super thick rough boards are subjected to post-processing. (If you are purchasing a large board, you can skip this stage.)
3. Polishing. The polishing stage has two parts: rough grinding and fine grinding.
Rough grinding: The qualified products in the previous process and the rough board with fixed thickness are roughed first with a grinder. At present, the grinders are mainly hand-held grinders and multi-head continuous grinding and polishing machines. After the wool board is dry, check the surface of the board. The effect of the board is good, and you can directly perform fine grinding. If the quality of the board is found to be unsatisfactory, you can brush the surface of the wool board and apply a layer of resin glue to The small holes, small cracks, chicken feet and other defects on the wool board can be repaired, and the surface of the wool board can be better and the glossiness higher. In good weather, the resin usually can dry in more than half an hour. If the weather is bad, it will take 1-2 hours to dry. It is best to wait for it to dry before fine grinding. In some factories, the wool board is washed and inspected without rough grinding, and then glue is applied directly to the wool board (the problematic). Usually, granite is brushed less and marble is brushed more.
Fine grinding: Use a polisher to polish the qualified or repaired mats one by one into matte boards. Remember to use red crayons for the unrepairable cracks, light colors, stone gall, and sweeping defects in the matte boards. Mark it out on the board so that the next process can be found in time, and can avoid these defects to process small-size components, such as baffles or thickened edges. Generally, the gloss of European and American orders must be above 90° (or processed according to customer requirements, if some stone types cannot meet the requirements, please consult with the customer). At the same time, the flatness limit tolerance of the European and American standard matte board is 0.8MM, and the allowable tolerance value of the thickness limit tolerance is plus or minus 1MM.
4. Trimming. Cut the qualified matte board in the front according to the requirements of the production order, and cut out the various parts of the table panel — main table, rear baffle, side baffle, front baffle, etc. When cutting, pay attention to the surface before checking, pay attention to the stone defects marked before, and avoid cracks, dark spots, color lines, stains, sweeping, etc., and no yin and yang surfaces. At the same time, it is necessary to ensure that the geometric dimensions, angular dimensions, and diagonal dimensions of the finished product after cutting are accurate, and no chipping or corner drop is allowed. If the back of the countertop needs to be glued, the edges, edges, and corners of the back must be kept intact to facilitate subsequent edge processing.
5. Edge processing. Edge processing refers to the processing of the edge of the countertop, whether it is a simple straight edge or a special-shaped edge (bottlenose edge, duck mouth edge, etc.). If the customer does not require the side to be thickened, the table can be processed directly (car side). If the customer requires a thicker side, then the side of the table must be thickened first. The specific method is to use a small cutting machine to smooth the place after adding, and then roughen the bonding surface into a rough surface for more firm bonding, then apply glue to bond, and finally fix it with a clamp. When bonding, pay attention to the gap between the two plates on the bonding surface as small as possible, preferably 0.1 ~ 0.2mm. After the glue dries, the edge can be processed. Advanced factories use special profiling edging machine with manual polishing assistance, while ordinary factories use manual cutting and polishing.
6. Digging basin drilling. It is to open the basin mouth, faucet hole, and the installation hole of the under-counter basin on the countertop. The opening is usually made by a machine, and the mouth of the basin is usually opened manually, or the four corners of the washbasin are first opened by an opener and then manually cut.
7. Polishing and repairing. Repairing is to repair the damage (slightly uneven or missing corners, etc.) or other natural defects caused by careless processing. Pay attention to the use of glue close to the color of the stone. Polishing is to polish the smooth surface of the entire countertop. After polishing, the gloss is required to be above 90°. At the same time, the surface becomes a mirror gloss, without bumps and waves, and the straightness of the junction is maintained in a straight line. The gloss of the edge of the countertop and the top of the washbasin should also be the same as the surface of the sky. It is usually done with a hand grinder. If the effect is good, a large grinder can be used. The countertops that are composed of multiple components should be patched and repaired and polished to avoid problems when waiting for the trial.
8. Trial assembly inspection. The panel will be inspected piece by piece, and the unqualified products shall be replaced or reworked in time. At the same time, for composite countertops that are not a single product, in addition to the smoothness of the edge, the feel and the flatness of the plate, etc., it is also necessary to try the combination. Pay attention to the unity of the design and color of the combined countertops, the splicing degree of the interface, and the combination The left and right order must be accurate according to the drawings.
Also, if the opening of the washbasin is only 7 or 8cm away from the side, it needs to be reinforced with steel bars. Even if this distance is exceeded, the steel bars must be reinforced on the back if requested by the customer. After the inspection, if the customer requires protection (waterproof treatment, etc.), then protection can be done.
9. Packaging. When packaging, the product is packaged according to customer requirements or stone quality. The blunt surface is opposite to the blunt surface, and a scratch-resistant soft film is sandwiched between the smooth surfaces. As for some stones that are afraid of scratches, like general darker stones (such as Shanxi Black), they will be coated to prevent scratches from affecting the viewing. The countertop should be placed vertically so that the stone is stressed vertically and never horizontally. It is best to pack all the countertops into a whole without loosening.
Stone countertops mainly include granite countertops, marble countertops, sandstone countertops, slate countertops, limestone countertops, and quartz countertops. The mainstream is granite and marble countertops. In terms of production quantity and application scope, Granite countertops are the most extensive. Probably because of the wear and corrosion resistance of granite.